Air-motor



W. E. EASTMAN;

A-IR MOTOR.

Patented May 22,1883.

Witnesses:

V UNITED STATES PATENT OFFICE.

WILLIAM E. EASTMAN, OF BOSTON, MASSACHUSETTS.

AIR-MOTOR.

SPECIFICATION forming part of Letters Patent No. 278,228, dated May 22, 1883.

Application filed December 7, 1882. (ModeLl 7 To all whom it may concern:

Be it known that I, WILLiAM E. EASTMAN, a citizen of the United States, residing at Boston, in the county of Sufiolk and State of Massachusetts, have invented certain new and useful Improvements in Air-Motors, of which the following is a specification, reference being sidered the piston-head of the engine.

had therein to the accompanying drawings, in whieh- Figure 1 is a side elevation of a motor-engine constructed in accordance with myinvention. Fig. 2 is a section of the same with the diaphragm distended. Fig.3 is asimilarview, with the diaphragm collapsed or in a horizontal position. Fig. 4 is a view of a modification showing valve devices. Fig. 5 is a view of the cam and valve-rod detached.

Similar letters of reference in the several figeconomical motor-engine for using compressed air, steam, or other elastic fluid, and, further, to do away with much friction now incident to machines or engines of this character.

While I do not intend to limit myself to the use of compressed air, I describe the use of my motor therewith for convenience.

By reference to the drawiugs,itwill be seen I that the disk or plate B, which is rigidly se-' cured to the piston-rod b, is actuated by an elastic expansible diaphragm, A, which is forced upward by the pressure of air entering the chamber from below by the pipe G. The hole or opening a at or near the center of the diaphragm is considerably larger than the diameter of that portion of the piston-rod 1) extending below'the plate B. This plate B is analogous to and for convenience may be con- Upon admission of air under pressure to the chain her it would naturally be supposed that it I would escape by the opening a, and after having forced the piston head or plate B a short distance away from the diaphragm it would then continue to flow uninterruptedly without imparting further motion to .any part of the machine. This, however, is not the case. As soon as the plate or piston-head is forced down upon the diaphragm the expansive force of the air within the chamber is exerted not only upon the plate through the opening a, (and of course upon the lower end of the piston-rod,)

but upon the whole surface of the diaphragm as well, which readily yields and transmits a pressure proportional to the area in contact with the plate or pistonhead. The. escape, then, of all except a thin stratum of air being prevented, the pressure within the chamber causes the elastic expansible diaphragm B to bulge vertically and expand, carrying the piston upward with it and rotating the. crankshaft E. and balance-wheel F. At a certain point, however, (which should be when the crank-wrist is a little above the center of the shaft,) the diaphragm becomes so distended and tense that it cannot any longer follow the plate up and give power to it and the momentum of the balance-wheel F carries the plate or piston-head away from it, uncovering the opening a. At this point the pent-up air within the chamber quickly and easily escapes through the now distended opening a, which is normally enough larger than the piston-rod to allow all the air entering the chamber to escape when the plate is not in contact with the diaphragm, and which is considerably enlarged when the diaphragm is distended. It will be readily understood that notwithstanding the constant flow of air to the chamber the diaphragm is not thereby prevented from resuming a horizontal or very nearly horizontal position, and, also, that no air escapes when the plate or piston-head is in contact with the plate, and is held there by the slight resistance due to the workingparts of the machine. Now, by momentum of the balancewheel,the crank completesitsrevolution, bringor chambered upon its upper surface, with the,

exception of a narrow rim upon which the peripheral portion of the diaphragm rests. This chamber or cavity in the bed-piece may be con sidered the equivalent of the cylinder in a steam-engine. Thebed-pieceisscrew-threaded around its circumference at the top, and the top piece, 1), likewise circular in horizontal I of this motor is'very rapid, and although it' section at its base, is also threaded upon its inside circumference to screw down upon the bed-piece and hold firmly the diaphragm.

To prevent wrinkling and displacing'of the diaphragm by the action of the top piece when screwed down, I introduce a metal ring, K, smooth upon its upper surface, to allow the top piece to slide over it, and press it down upon the top of the diaphragm.

As will be seen, the top piece, D, is provided with upwardly-projecting arms which carry at their tops journal-boxes for the crank-shaft E, which carries at one of its ends the balancewheel F, and to which is connected the piston-rod, as hereinbefore set forth. The action can be made of large size to give considerable power, it is best adapted to runninglight machinery, hand-tools, and the like-such, for instance, as dental pluggers and excavators, small grinding tools, perforating-pens, and, generally, tools and instruments of that class where rapid motion and little power are required.

In Figs. at and 5 the motor is shown with a valve attachment, which, though not essential to the working of the machine, I apply to economize the compressed air. In this case the air, instead ofentering at the central portion of the chamber, enters by the inductionport g, very near the side of the chamber. A valve-rod, I, armed at its upper end with a friction-roller, L, and at its lower end with a ball or hemisphere of suitable material, preferabl y soft rubber, receives proper motion from the cam H, mounted upon the crank-shaft E. This cam is so set thatjustas the exhaustoccurs it forces down that portion of the diaphragm immediately above the induction-port. This portion of the diaphragm, acting as a stopper, prevents the entrance of more air to the chamber until, at the proper time, (which isjust as, in its descent,-the plate B reaches the diaphragm,) the valve-rod, released by the cam,

in turn relieves the diaphragm. The valve-rod does not require any spring to keep it in contact with the cam, as it rides continuously upon the diaphragm. The opening through the arm through which it passes is so con- 'structed as to keep the friction-roller always parallel to the cam, and to give to the valverod a. true reciprocating motion in a right line. I As shown in the accompanying drawings, the piston-rod is coupled direct to the crank, which subjects the plate B to a slighttilt-ing, due to the horizontal throw of the crank. This in small machines, where such throw is slight, is not objectionable, a short stroke and quick motion being desired, but in larger machines the piston-rod may be provided with a crosshead running in ways, andthe connection to the crank be made in the manner usual in steam-engines by a connecting-rod. This modification is so obvious that I have not deemed it necessary to show it.

Having thus described my invention, I claim as new- 1. In a motor-engine, a perforated elasti diaphragm actuated by an elastic fluid, imparting motion to a detached piston.

2. In a motor-engine, a perforated elastic diaphragm, actuated by an elastic fluid, and a detached piston, which, during a part only of the stroke, prevents the escape of elastic fluid through the perforation by contact with said diaphragm.

3. In motor-engine, a perforated elastic diaphragm, actuated by an elastic fluid, which imparts motion to a detached piston through a part only of the stroke and resumes its nor mal position by its own elasticity, the exhaust meanwhile taking place through'the perforation when by momentum it is uncovered by the travel of the piston.

4. A motor-engine provided with an elastic perforated diaphragm, actuated by an elastic 'fluid, which imparts motion to the piston and is retracted by its own elasticity, the exhaust taking place through the perforation, substantially as described.

5. A motor-engine provided with an elastic perforated diaphragm, actuated by an elastic fluid, which imparts motion to the piston, and, during a part of the stroke, prevents the escape of the elastic fluid through the perforation in said diaphragm, in the manner described.

6. The elastic perforated diaphragm A, in combination with the piston-head B, operating substantially as described, and for the purpose specified.

7. The elastic perforated diaphragm A, in combination with the piston-head B and mechanism for converting reciprocating into rotary motion, substantially as described.

8. A motor-engine in which an elastic diaphragm, actuated by an elastic fluid, imparts motion to the piston, and in which the said diaphragm and piston are in contact only during a portion of the stroke.

9. The construction, substantially as herein set forth, consisting, essentially, of a chamber or cylinder receiving a continuous supply of elastic fluid under pressure, an elastic perforated diaphragm, a detached piston so arranged as to prevent the escape of elastic fluid through the perforation when in contact with said diaphragm, and devices for converting reciprocating into rotary motion, all operating substantially as described.

In testimony whereof I aflix my signature in presence of two witnesses.

WILLIAM E. EASTMAN.

Witnesses:

WM. H. llliLLER, H. D. LOGAN. 

